Towards Authorization and Batch Validation for NFTs: A Cryptographic Generic Framework

The rapid growth in the NFT (Non-fungible token) market has offered a wide variety of opportunities for scammers, fraudsters, wash tradings, and so on. One of the most urgent security issues is how to efficiently authorize and validate the ownership to make the NFT ecosystem avoid infringement and counterfeiting. By exploiting linear homomorphic tagging and robust digital watermarking technologies, this article proposes a generic framework for ownership authorization and batch validation of NFTs. Within this framework, the digital artwork creators can authorize the ownership to a buyer before the NFT is minted in the public blockchain. Anytime in the future who questions the ownership of a claimant can initiate a validation procedure to get an auditing report by running a Challenge-Response protocol that supports efficient batch verification. The completeness and soundness of the proposed framework have been proven by assuming a secure homomorphic tag scheme and a robust watermarking scheme. We also present instantiations of the generic construction, especially with $\Pi _{Pub}$, one can outsource the validation procedure to the public blockchain to release local computation burden. A series of elaborated experiments have shown our proposed framework is practical and efficient.